The present invention relates to the new and distinct x Mangave hybrid plant, x Mangave ‘Thunderbird’ that was hybridized by the inventor at a wholesale perennial nursery in Zeeland, Mich., USA as a cross between a proprietary unnamed x Mangave hybrid known only as 12-41-5 (not patented) as the female or seed parent times a proprietary selection of Manfreda virginica named AL-55 (not patented) as the male or pollen parent. The cross was performed Oct. 13, 2014 and seeds were harvested and sown early winter of 2015. Through trials at the same nursery the plant was assigned the breeder code 15-4-3. The new plant has been successfully asexually propagated by sterile shoot-tip tissue culture and by basal offsets at the same nursery in Zeeland, Mich. The asexual tissue culture propagation has been found to produce stable and identical plants that maintain all the unique characteristics of the original plant.